The epic fitting of my crankshaft

View previous topic View next topic Go down

The epic fitting of my crankshaft

Post  parador on Wed 27 Dec 2017, 4:10 pm

There don't seem to be many posts at the moment(apart from Lynn) so I thought I would make a confession and tell you all my crankshaft story.

The story begins(from an earlier post of mine) with the front spectacle plate.  My spectacle plate appeared to pull in the hornplates.  When I attempted to fit the dummy crankshaft it just locked up despite all manner of adjustments with the LHB housing.  When I removed the front spectacle plate I could adjust the dummy crank to turn.  

In desperation I phoned Steve B and to cut a long story short I gave him the measurements between the hornplates and he posted out a drawing to me so that I could check the fit.  It needed further modification which I gave him over the phone and he arranged the laser cutting of a new spectacle plate which duly arrived after a couple of weeks.  The new spectacle plate fitted perfectly and did not draw the hornplates together when tightened-up.  [Superb service from STW and SB is such a nice guy].

Onto the actual crankshaft.  I decided to concentrate on the LHB as it seemed simpler to fit to the crank, being only of two pieces.  This is where I had a brain F.  I looked at the crank and it was shinier where the shaft steps up a couple of mm in diameter so I assumed that the bearing fitted there.  I had already bought some Timesaver lapping compound and had read on a couple of posts that medium and fine tended to be used on the eccentrics so I decided to follow suit with the LHB.  Now the bearing was miles off fitting the shaft so i used wet and dry to get it somewhere near so that I could use the Timsaver medium.  I placed the crank on the bench and started the rotate each bearing half on the shaft.  After a day of slow progress I decided to 'up the ante' and throw caution to the wind and use the 40 grade Timesaver.  Progress improved with the 40 and after a further 4 days I had the perfect LHB surface and a right arm twice the size from when I started Very Happy .  The RHB was a closer fit to the shaft(because I was fitting it to the correct place).  I used wet and dry to get the RHB close then Timesaver again but this time it fitted only in about 1 hour.  I followed the 'crankshaft posts' of Lynn and highpressure , which are very good, and fairly easily fitted both the L and R bearings to the housings on the hornplates.  I decided not to fully assemble the crankshaft to keep it light as possible and then attempted to fit it to engine.  With the bearings on the crankshaft the crank seemed to be about 4" short.  I could not believe it and after about 1/2 hour looking at it I decided that STW had made a mistake and given me a short crankshaft.  I rang Steve and explained the problem and as we discussed the issue I realised that I had stupidly fitted the LHB on the wrong diameter of the shaft.  When I looked at the ISO drawing it was so obvious.  I had wasted a week of mindless LHB fitting to be left with a bearing that fitted perfectly in the wrong place but was now useless.  STW to the rescue and I had a new bearing in a couple of days.  Surprise surprise this new bearing was really easy to fit to the correct place on the shaft.

Anyway after vowing to be more careful in the future and also to look more closely at the ISO's, the actual fitting of the crankshaft was not to bad - again following the excellent posts on here.  The main issue I had was that when the bearing caps were tightened down the crankshaft locked-up.  After disassembly several times I located the problem to the bearing adjuster plate on the RHB-this needed to be filed down and also the housing where it sits.  I also needed to drill the oil holes on the LHB as they were about 3mm out of place.

The crankshaft can now be turned with 2 hands(thank god) and I plan to assemble the other bits onto it tomorrow and then paint asap.

I hope you all have had a good Christmas and I wish you all the best for the New Year.
Regards
Martin

parador

Number of posts : 44
Registration date : 2008-07-02

View user profile

Back to top Go down

Re: The epic fitting of my crankshaft

Post  lynnr on Wed 27 Dec 2017, 7:20 pm

Hi

Well I am glad you got everything sorted out in the end.
avatar
lynnr

Number of posts : 2908
Age : 49
Location : Highland, 4inch showman
Registration date : 2010-08-06

View user profile http://www.pbase.com/uisge

Back to top Go down

Re: The epic fitting of my crankshaft

Post  Simon C on Fri 29 Dec 2017, 1:36 pm

Hi Martin
I am sorry to be the bearer of bad news but the most painful part of the build is still to come for you!
The first run be it air or steam will give you a smile so wide that it will make your face hurt for a week.
It will change all the bad memories in to challenges you have overcome on the way.
With only 2 kits left to complete my showman’s and the boiler inspector due just after New Year my next face aching moment might be just around the corner.
All the best for the remains of the silly season and keep up the good work.

Simon C (a full roofer)
avatar
Simon C

Number of posts : 24
Location : Derby
Registration date : 2017-07-07

View user profile

Back to top Go down

Re: The epic fitting of my crankshaft

Post  parador on Fri 29 Dec 2017, 7:53 pm

Hi Simon

It's certainly turning into a journey.
Regards
Martin

parador

Number of posts : 44
Registration date : 2008-07-02

View user profile

Back to top Go down

Re: The epic fitting of my crankshaft

Post  Sponsored content


Sponsored content


Back to top Go down

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum